U.S. patent application number 14/834166 was filed with the patent office on 2015-12-17 for dual sensor camera.
The applicant listed for this patent is DigitalOptics Corporation. Invention is credited to John D. Griffith, Jisoo Lee.
Application Number | 20150365605 14/834166 |
Document ID | / |
Family ID | 42737234 |
Filed Date | 2015-12-17 |
United States Patent
Application |
20150365605 |
Kind Code |
A1 |
Griffith; John D. ; et
al. |
December 17, 2015 |
DUAL SENSOR CAMERA
Abstract
A dual sensor camera that uses two aligned sensors each having a
separate lens of different focal length but the same f-number. The
wider FOV image from one sensor is combined with the narrower FOV
image from the other sensor to form a combined image. Up-sampling
of the wide FOV image and down-sampling of the narrow FOV image is
performed. The longer focal length lens may have certain
aberrations introduced so that Extended Depth of Field (EDoF)
processing can be used to give the narrow FOV image approximately
the same depth of field as the wide FOV image so that a noticeable
difference in depth of field is not see in the combined image.
Inventors: |
Griffith; John D.;
(Rochester, NY) ; Lee; Jisoo; (Sunnyvale,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DigitalOptics Corporation |
San Jose |
CA |
US |
|
|
Family ID: |
42737234 |
Appl. No.: |
14/834166 |
Filed: |
August 24, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14570736 |
Dec 15, 2014 |
9118826 |
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14834166 |
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14035635 |
Sep 24, 2013 |
8913145 |
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14570736 |
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12727973 |
Mar 19, 2010 |
8542287 |
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14035635 |
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61161621 |
Mar 19, 2009 |
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Current U.S.
Class: |
348/240.2 |
Current CPC
Class: |
G02B 27/0075 20130101;
G06T 5/003 20130101; H04N 5/2628 20130101; H04N 5/232 20130101;
H04N 5/2258 20130101; H04N 5/23232 20130101; H04N 5/2253 20130101;
H04N 5/2251 20130101; H04N 5/23296 20130101; H04N 5/272 20130101;
G06T 5/50 20130101; G06T 2207/20221 20130101 |
International
Class: |
H04N 5/232 20060101
H04N005/232; H04N 5/262 20060101 H04N005/262; H04N 5/272 20060101
H04N005/272; H04N 5/225 20060101 H04N005/225 |
Claims
1. A method of generating a combined image with a camera, the
method comprising: receiving light with a first sensor from a first
lens having a first focal length; capturing a first image formed on
the first sensor with the first sensor; receiving light with a
second sensor from a second lens having a second focal length that
is longer than the first focal length; capturing a second image
formed on the second sensor with the second sensor, the combination
of the first sensor and the first lens and the combination of the
second sensor and the second lens being directed toward the same
subject; combining the first image and the second image together to
form a single combined image with the second image forming a
central portion of the single combined image and a peripheral
portion of the first image forming a peripheral portion of the
single combined image; and applying a mask to at least one of the
first image and the second image before the first image and the
second image are combined together, the mask blocking a portion of
the image to which the mask is applied; and wherein the combining
of the first and the second images includes at least one of
up-sampling the first image and down-sampling the second image.
2. The method of claim 1, wherein the mask is applied to the first
image, the mask blocking a central portion of the first image and
allowing the peripheral portion of the first image to be used in
forming the single combined image.
3. The method of claim 1, wherein the mask is applied to the second
image, the mask blocking a peripheral portion of the second image
and allowing a central portion of the second image to be used in
forming the single combined image.
4. The method of claim 1, wherein the up-sampling is performed with
a scaling factor A and the down-sampling is performed with a
scaling factor B.
5. The method of claim 4, wherein: Z is the ratio of the field of
view (FOV) of the first sensor to the FOV of the second sensor; and
Z=A.times.B.
6. The method of claim 5, wherein A is a value in the range between
and including 1 and Z.
7. The method of claim 4, wherein: A is a value in the range
between and including 1 and Z; and Z is the ratio of the field of
view (FOV) of the first sensor to the FOV of the second sensor.
8. The method of claim 1, wherein the first lens and the second
lens have substantially equal f-numbers.
9. The method of claim 1, wherein the first lens and the second
lens are selected such that the illuminance on the first sensor and
the illuminance on the second sensor are equivalent.
10. The method of claim 1, wherein the amount of up-sampling is
determined based at least in part on a digital zoom setting
selected by a user.
11. The method of claim 1, wherein the central portion and the
peripheral portion of the single combined image have similar levels
of at least one of brightness, background noise, motion artifacts,
and depth of field.
12. The method of claim 1, wherein: the second lens has been
designed to work with extended depth of field (EDoF) processing by
the introduction of specified aberrations into the second image
formed on the second sensor; and the second image is subjected to
EDoF processing to focus the second image.
13. The method of claim 12, wherein: the first image has a first
depth of field determined by the combination of the first sensor
and the first lens; and the EDoF processing of the second image
results in the second image having a second depth of field that is
substantially equal to the first depth of field.
14. The method of claim 12, wherein: the first lens has been
designed to work with extended depth of field (EDoF) processing by
the introduction of specified aberrations into the first image
formed on the first sensor; and the first image is subjected to
EDoF processing to focus the first image.
15. A method of generating a combined image with a camera, the
method comprising: receiving light with a first sensor from a first
lens having a first focal length; capturing a first image formed on
the first sensor with the first sensor; receiving light with a
second sensor from a second lens having a second focal length that
is longer than the first focal length; capturing a second image
formed on the second sensor with the second sensor, the combination
of the first sensor and the first lens and the combination of the
second sensor and the second lens being directed toward the same
subject; and combining the first image and the second image
together to form a single combined image with the second image
forming a central portion of the single combined image and a
peripheral portion of the first image forming a peripheral portion
of the single combined image; and wherein the step of combining the
first and the second images includes at least one of up-sampling
the first image with a scaling factor A and down-sampling the
second image with a scaling factor B; A is a value in the range
between and including 1 and Z; and Z is the ratio of the field of
view (FOV) of the first sensor to the FOV of the second sensor.
16. The method of claim 15, wherein the first lens and the second
lens have substantially equal f-numbers.
17. The method of claim 15, wherein the first lens and the second
lens are selected such that the illuminance on the first sensor and
the illuminance on the second sensor are equivalent.
18. The method of claim 15, wherein the amount of up-sampling is
determined based at least in part on a digital zoom setting
selected by a user.
19. The method of claim 15, wherein the central portion and the
peripheral portion of the single combined image have similar levels
of at least one of brightness, background noise, motion artifacts,
and depth of field.
20. The method of claim 15, wherein: the second lens has been
designed to work with extended depth of field (EDoF) processing by
the introduction of specified aberrations into the second image
formed on the second sensor; and the second image is subjected to
EDoF processing to focus the second image.
21. The method of claim 20, wherein: the first image has a first
depth of field determined by the combination of the first sensor
and the first lens; and the EDoF processing of the second image
results in the second image having a second depth of field that is
substantially equal to the first depth of field.
22. The method of claim 20, wherein: the first lens has been
designed to work with extended depth of field (EDoF) processing by
the introduction of specified aberrations into the first image
formed on the first sensor; and the first image is subjected to
EDoF processing to focus the first image.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent
application Ser. No. 14/570,736 (now U.S. Pat. No. 9,118,826),
entitled "DUAL SENSOR CAMERA," filed on Dec. 15, 2014 by at least
one common inventor, which is a continuation of then co-pending
U.S. patent application Ser. No. 14/035,635 (now U.S. Pat. No.
8,913,145), entitled "DUAL SENSOR CAMERA," filed on Sep. 24, 2013
by at least one common inventor, which is a continuation of then
co-pending U.S. patent application Ser. No. 12/727,973 (now U.S.
Pat. No. 8,542,287), entitled "DUAL SENSOR CAMERA," filed on Mar.
19, 2010 by at least one common inventor, which claims the benefit
of U.S. Provisional Application No. 61/161,621, entitled "DUAL
SENSOR CAMERA," filed on Mar. 19, 2009, all of which are
incorporated herein by reference in their entireties.
BACKGROUND
[0002] Digital camera modules are currently being incorporated into
a variety of host devices. Such host devices include cellular
telephones, personal data assistants (PDAs), computers, and so
forth. Consumer demand for digital camera modules in host devices
continues to grow.
[0003] Host device manufacturers prefer digital camera modules to
be small, so that they can be incorporated into the host device
without increasing the overall size of the host device. Further,
there is an increasing demand for cameras in host devices to have
higher-performance characteristics. One such characteristic that
many higher-performance cameras (e.g., standalone digital still
cameras) have is the ability to vary the focal length of the camera
to increase and decrease the magnification of the image, typically
accomplished with a zoom lens, now known as optical zooming.
Optically zooming is typically accomplished by mechanically moving
lens elements relative to each other, and thus such zoom lenses are
typically more expensive, larger, and less reliable than fixed
focal length lenses. An alternative approach for approximating this
zoom effect is achieved with what is known as digital zooming. With
digital zooming, instead of varying the focal length of the lens, a
processor in the camera crops the image and interpolates between
the pixels of the captured image to create a "magnified but
lower-resolution image. There have been some attempts to use two
different lenses to approximate the effect of a zoom lens. It has
been done in the past with film cameras in which the user could
select one of two different focal lengths to capture an image on
film. More recently, a variation on this concept with camera
modules has been disclosed in U.S. Pat. Pub. No. 2008/0030592, the
entire contents of which are incorporated herein by reference,
which discusses a camera module with a pair of sensors, each having
a separate lens through which light is directed to the respective
sensor. In this publication, the two sensors are operated
simultaneously to capture an image. The respective lenses have
different focal lengths, so even though each lens/sensor
combination is aligned to look in the same direction, each will
capture an image of the same subject but with two different fields
of view. The images are then stitched together to form a composite
image, with the central portion of the composite image being formed
by the relatively higher-resolution image taken by the lens/sensor
combination with the longer focal length and the peripheral portion
of the composite image being formed by a peripheral portion of the
relatively lower-resolution image taken by the lens/sensor
combination with the shorter focal length. The user selects a
desired amount of zoom and the composite image is used to
interpolate values therefrom to provide an image with the desired
amount of zoom. Unfortunately, the disclosure in this publication
is largely conceptual and lacks in certain details that would be
needed to provide optimal performance.
[0004] The foregoing examples of the related art and limitations
related therewith are intended to be illustrative and not
exclusive. Other limitations of the related art will become
apparent to those of skill in the art upon a reading of the
specification and a study of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a block diagram of a camera.
[0006] FIG. 2 is an illustration of the combination of two images
into a single combined image.
[0007] FIG. 3 is an illustration of digital zooming of the combined
image.
DETAILED DESCRIPTION
[0008] The following description is not intended to limit the
invention to the form disclosed herein. Consequently, variations
and modifications commensurate with the following teachings, and
skill and knowledge of the relevant art, are within the scope of
the present invention. The embodiments described herein are further
intended to explain modes known of practicing the invention and to
enable others skilled in the art to utilize the invention in such,
or other embodiments and with various modifications required by the
particular application(s) or use(s) of the present invention.
[0009] A camera 10 is shown in FIG. 1. The camera 10 may include a
first lens 12 having a relatively-shorter focal length and a first
sensor 14 that are located proximate to and substantially aligned
with a second lens 16 having a relatively-longer focal length and a
second sensor 18. By having the combined first lens and first
sensor aligned with the combined second lens and second sensor, the
sensors can each obtain an image of substantially the same subject.
Of course, due to the different focal lengths of the lenses 12 and
16, the first sensor 14 will obtain an image of the subject with a
relatively-wider field of view (FOV) as compared to the
relatively-narrower FOV of the image obtained by the second sensor
18.
[0010] In most cases, each sensor 14 and 18 would perform certain
basic image processing algorithms such as white balancing, and so
forth. The second lens 16 has an additional reference number 17 to
indicate that it is designed to work with Extended Depth of Field
(EDoF) processing, which may involve introducing specific
monochrome or chromatic aberrations into the lens design as
determined by the EDoF technology, or by adding a phase mask (e.g.,
a cubic phase mask) to the lens. Each sensor may also perform
additional image processing such as EDoF processing. In this
example, the EDoF processing 20 is shown as part of sensor 18 and
is not a part of sensor 14. In other examples, not illustrated
here, each of the sensors 14 and 18 may include EDoF processing, or
other combinations may be employed such as sensor 14 including EDoF
processing while sensor 18 does not. Similarly, while this example
shows only the second lens 16 being designed to work with EDoF
processing, any other combination may be possible, including each
of the lenses 12 and 16 being designed to work with EDoF
processing. The lenses 12 and 16 could be made of any acceptable
material, including plastic, glass, optical ceramic, diffractive
elements, or a composite.
[0011] EDoF processing will be discussed here generally, but much
greater detail can be found in the literature associated with the
following companies that are believed to be actively developing
EDoF technology: DxO Labs, S.A. of Boulogne, France (under its
DIGITAL AUTO FOCUS.TM. trademark); CDM Optics, Inc. of Boulder,
Colo. (under its WAVEFRONT CODING.TM. trademark); Tessera, Inc. of
San Jose, Calif. (under its OPTIML FOCUS.TM. trademark); and Dblur
Technologies Ltd. of Herzliya Pituach, Israel (whose relevant IP
assets are now owned by Tessera)(under its SOFTWARE LENS.TM.
trademark). In addition, the following patents, published patent
applications, and technical articles are believed to disclose
related EDoF technology: PCT/FR2006/050 197; PCT/FR2008/05 1265;
PCT/FR2008/05 1280; U.S. Pat. No. 5,748,371; U.S. Pat. No.
6,069,738; U.S. Pat. No. 7,031,054; U.S. Pat. No. 7,218,448; U.S.
Pat. No. 7,436,595; PCT/1L2004/00040; PCT/1L2006/01294;
PCT/1L2007/00381; PCT/IL2007/000382; PCT/IL2007/00383;
PCT/IL2003/000211; and Dowski & Cathey "Extended Depth of Field
Through Wavefront Coding," Applied Optics, 34, 11, p. 1859-66
(1995); the contents of each of which are incorporated herein in
their entirety.
[0012] Depth of field refers to the depth of the longitudinal
region in the object space that forms an image with satisfactory
sharpness at some focus position. In ordinary optics, the paraxial
depth of field is determined by the allowable paraxial blur, the
lens focal length, and the lens f-number. See for example, Warren
J. Smith, Modern Optical Engineering, 3rd Edition, Chapter 6.
Within the paraxial model, the depth of field of the lens is fixed
once these choices are made.
[0013] A more sophisticated model of depth of field in ordinary
optics includes the lens aberrations and diffraction effects. This
model typically analyzes the depth of field using through focus
Modulation Transfer Function (MTF) calculations. In this model, the
depth of focus depends on the aberrations of the lens and the
diffraction occurring at the f-number of the lens. The depth of
field is determined by these factors plus the focal length of the
lens. As the aberrations become smaller, the depth of field of the
lens approaches a limit set by diffraction, which is determined by
the lens f-number, the focal length of the lens, and the allowable
MTF drop at various object distances. Similarly to the paraxial
depth of field model, the maximum depth of field is set by the
allowable blur (MTF drop), the lens f-number, and the lens focal
length.
[0014] In the ordinary optical design process, the goal is to
minimize the aberrations present in the lens, consistent with size
and cost constraints. The goal is form a sharp image when the lens
is in focus. In extended depth of field (EDoF) technology, the
depth of field is increased by a combination of the use of a
specially designed lens together with EDoF image processing of the
image captured by the sensor. Various types of EDoF technology have
been proposed or implemented by various companies (some of which
are mentioned above).
[0015] The various EDoF technologies all require that the lens not
form the sharpest image possible at best focus, but rather form an
image that is degraded in a special way. In one implementation,
this is achieved with a phase mask, which "degrades" the image. In
other implementations, this is achieved by introducing specified
monochromatic or chromatic aberrations into the lens design. A
sharp image is then recovered through signal processing techniques.
The details of how the image is degraded and how it is recovered
differ between the various EDoF technologies.
[0016] In the design of a lens for use with EDoF technology, the
goal is not to minimize the aberrations present in the image formed
by the lens, but rather to introduce with the use of a phase mask
or a special set of aberrations into the image formed by the lens
that allows recovery of a sharp image over an extended depth of
field. The exact aberrations or type of phase mask that must be
introduced depends on the particular EDoF technology in use. In
some cases, these aberrations are introduced by the addition of an
additional optical element, such as a cubic phase element (or cubic
phase mask), to an otherwise sharp lens. In other cases, axial
color or monochromatic aberrations may be introduced into the lens
design itself.
[0017] In the example shown in FIG. 1, lens 16 has certain
aberrations therein that are designed for use with the EDoF
processing 20 that will be performed by the sensor 18 that
corresponds to the lens 16. In this example, the lens 16 may be a
lens having a focal length of 7.2 mm, a field of-view (FOV) of 32
degrees, and an f-number of f/2.8. The lens 12 may be a lens having
a focal length of 3.62 mm, an FOV of 63 degrees, and an f-number of
f/2.8. These lens specifications are merely exemplary and any other
suitable lens characteristics could be acceptable. In addition, one
or both of the lenses 12 and 16 could be variable focal length
(zoom) lenses.
[0018] In the example shown in FIG. 1, the two lenses 12 and 16
have the same f-number so that the illuminance of the light
received at the sensors 14 and 18 is equivalent. With equivalent
illuminance, the sensors can be operated at similar levels of
amplification and with similar exposure times. In this manner, the
separate images captured by the separate sensors 14 and 18 can be
of similar levels of brightness and contrast. By having similar
levels of amplification, the background noise in each image will be
similar. By having similar exposure times, artifacts in each image
due to subject motion will be similar. By maintaining similarity as
to these two characteristics in the two images, the composite image
formed from the two images will be more acceptable to the user.
Examples of sensors that could be used for sensor 18 are Model Nos.
VD6826 and 69031953 (each of which include DxO EDoF algorithms) and
VD68031853 (which includes Dblur EDoF algorithms), each of which
are available from STMicroelectronics of Geneva, Switzerland.
Examples of sensors that could be used for sensor 14 are these same
sensors mentioned above (with EDoF processing turned off) or
similar sensors that do not have EDoF capabilities, such as VD6852
or VD6892. In this example, each of the sensors is a Bayer sensor,
which uses a color filter array over the array of separate pixels,
as is well known. Such sensors sense green light at every other
pixel, with the intervening pixels alternating between red pixels
and blue pixels. The raw sensed signals are later provided to a
demosaicing algorithm, which interpolates between the pixels to
obtain a full color signal for each pixel. However, the invention
is not limited to use with a Bayer sensor and will work equally
well with sensors having a different color filter array, cameras
based on time-sequential color, cameras using beamsplitters and
separate sensors for each color channel, and other camera
architectures, provided these architectures are consistent with the
operation of one of the underlying EDoF technologies.
[0019] In some cases, the camera 10 may be considered to include
only the functional portions described above. In other cases, these
portions (referred to collectively as a camera module 22) may also
be combined with certain downstream components as part of the
camera 10. In such case, the camera 10 may also include an image
signal processor (ISP) 24, a display 26, and user interface
controls 28. Of course, as is well known in the camera industry,
cameras may also typically include several other components that
are omitted here for simplification. For example, as non-limiting
examples, these other components may include batteries, power
supplies, an interface for the application of external power, a USB
or other interface to a computer and/or printer, a light source for
flash photography, auto-focus and image stability controls,
internal memory, one or more ports for receiving an external memory
card or device (e.g., an SD or xD memory card), and in the case of
the use of a camera in a mobile phone, a microphone, speaker,
transmitter/receiver, and an interface for an external microphone
and speaker (e.g., a Bluetooth headset).
[0020] The user interface controls 28 may include conventional
controls that are used to operate the camera, including controls to
instruct the camera to capture one or more images, as well as to
manipulate the images, and many other functions. The display 26 may
be a conventional display that displays images automatically as
directed by the ISP 24 or upon request by the user via the user
interface controls 28 and ISP 24. The ISP 24 includes certain
distortion-correction algorithms that smoothly match features
between the two separate images when the composite image is formed.
Further, the ISP 24 may include the demosaicing algorithm
(referenced above with regard to Bayer sensors), sharpening
algorithms, and other standard algorithms used in ISPs in such
applications. The ISP also includes algorithms to create the
combined image from the two captured images. A suitable approach
for combining the images is discussed in U.S. Pat. Pub. No.
2008/0030592, referenced above.
[0021] FIG. 2 shows both the image 50 from the first sensor (the
one with the wider FOV) and the image 52 from the second sensor
(the one with the narrower FOV). The wide FOV image 50 goes through
up-sampling 54, while the narrow FOV image 52 goes through
down-sampling 56. In order to ensure that the two images are
combined to form a single congruent image without any visible
mismatch between the appearance of image objects, the wider FOV
image 50 commonly undergoes an image up-sampling operation (i.e.
digital zoom) whose scaling factor, A, may range from 1 (i.e. no
up-sampling operation applied) to Z, where Z is the ratio of FOV of
the first sensor to the ratio of FOV of the second sensor. The
narrow FOV image 52 undergoes a down-sampling operation whose
scaling factor, B, is given by Z divided by A. Hence, the
relationship between the two scaling factors is generally given by
the equation:
Z=A.times.B
[0022] The amount of up-sampling 54 and down-sampling 56 represents
a different trade-off between the sharpness quality and the size of
the combined image. The up-sampling factor is generally controlled
by the "digital zoom" setting selected by the user; however, it is
possible to select a value of A which does not match the "digital
zoom" setting in order constrain the number of pixels in the
combined image. After the wide FOV image 50 has been up-sampled it
may optionally go through further sharpening 58. Then the wide FOV
image 50 has a mask 60 applied thereto, which serves to block a
central portion 62 of the image 50 while allowing a peripheral
portion 64 of the image 50 to be used in forming the combined image
66. After the narrow FOV image 52 has been down-sampled it has a
mask 68 applied thereto, which serves to block a peripheral portion
70 of the image 52 while allowing a central portion 72 of the image
52 to be used in forming the combined image 66. As differentiated
by a border 74 in the combined image 66, the central portion 76 of
the combined image 66 is taken from the narrow FOV image 52 while
the peripheral portion 78 of the combined image 66 is taken from
the wide FOV image 50.
[0023] FIG. 3 shows the digital cropping of the peripheral region
of the combined image 66 such that the resulting image has a
smaller FOV 80 corresponding to the "digital zoom" setting
specified by the user. This may be referred to as "digital zooming"
of the combined image 66.
[0024] In this figure, the central portion 76 of the combined image
66 is differentiated from the peripheral portion 78 by the border
74 (although the border 74 will not actually be visible to a user
in operation). In one zoomed image 82, the camera 10 has been
zoomed to a position where only the central portion 76 of the
combined image 66 (which is the narrow FOV image 52) is used. At
the other end of the spectrum, another zoomed image 83 can be
created, in which the combined image 66 is used. At an intermediate
position in the spectrum, a different zoomed image 84 can be
created. For this image, the central portion 76 of the combined
image 66 is expanded and only a fraction of the peripheral portion
78 of the combined image 66 is used.
[0025] Alternatively, the camera module 22 could include one or
more ISPs located thereon.
[0026] They could be separate from or integrated into the sensors.
Further, while the lenses 12 and 16 described herein are fixed
focal length, either or both could be variable focal length (zoom)
lenses.
[0027] It should be appreciated that with the camera 20 described
above, the combined image will have similar levels of brightness,
background noise, motion artifacts, and depth-of field. This will
make for a more pleasing and acceptable combined image. If the EDoF
technology were not utilized, this would be impossible to achieve.
This is because with conventional optics it is not possible to get
the same illuminance delivered to the image plane from two lenses
of different focal length while at the same time matching the depth
of field. One can choose to have the same image illuminance; for
example, by each of the lenses having an f-number of f/2.8. But in
such case, the depth of field will be much greater for the shorter
focal length lens. Alternatively, one can choose to have the same
depth of field; for example, with the focal lengths for the two
lenses used in the example described above in conjunction with FIG.
1, the longer focal length lens would need to have an f-number of
approximately f/11 to have the same depth of field of the shorter
focal length lens. But in such case, the optical power delivered by
the longer focal length lens (at f/11) would be 1/16.sup.th of the
optical power delivered by the shorter focal length. The camera 10
described above allows for the optical power and depth of field to
be the same for each lens/sensor combination. Of course, it would
also be possible to obtain the same optical power and depth of
field with different focal length lenses if the two different image
sensors were operated with different amounts of amplification or
with different exposure times. Unfortunately, this would change the
background noise level or motion artifact level, respectively,
between the two images.
[0028] One variation on the disclosure above is that there could be
some type or pre-cropping of the peripheral and central regions of
the wide FOV image prior to the-upsampling operation (to reduce the
processing and memory requirements of the image processing involved
in the upsampling operation).
[0029] Any other combination of all the techniques discussed herein
is also possible. The foregoing description has been presented for
purposes of illustration and description. Furthermore, the
description is not intended to limit the invention to the form
disclosed herein. While a number of exemplary aspects and
embodiments have been discussed above, those of skill in the art
will recognize certain variations, modifications, permutations,
additions, and subcombinations thereof. It is therefore intended
that the following appended claims and claims hereafter introduced
are interpreted to include all such variations, modifications,
permutations, additions, and sub-combinations as are within their
true spirit and scope.
* * * * *